The beverage bottle industry applies a lubricious transparent cold end coating (CEC) onto formed glass bottles to prevent surface damage and caustic attack of the glass bottles. Screen printed organic inks are typically applied directly upon a CEC. Unfortunately, the CEC can interfere with bonding of the organic ink and adhesion at the glass surface. Therefore, various materials have been evaluated as cross-linkers to promote adhesion on CEC's, on glass surfaces, and for use in other additives. As a result, particular chemistries and procedures for application of CEO's at bottling plants have been recommended. The basic chemistry necessary for improvement of bonding between the organic ink and glass surface is the addition of a silane to a CEC composition. The adhesion improvement between the organic ink layer and the CEC is mainly based on the cross-linking function of the materials.
Quality issues may arise with the CEC that can significantly impact hot caustic durability performance in returnable glass bottles. A bottler or decorator typically experiences significant field failures with many commercially available inks. This is likely due to poor CEC quality in terms of adhesion on glass and bonding with the organic inks. As noted, the CEC is transparent, as it is made of various clear mediums containing fatty acids, polymers, etc. Thus, there is currently no easy way to ensure that the CEC is present on the glass surface, that it contains the necessary silane, that it is applied uniformly, and/or that the CEC solution or coated bottles have not aged or degraded to an extent such that the silane no longer has the requisite surface functionality.
Therefore, the objectives of the present invention include improving adhesion of CECs on glass surfaces, improving bonding with organic inks, and providing fast and easy test methods for detection of the invisible and functional CEC and its components.